Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Physical based model for predicting the microstructural evolution at hot rolling
KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
Högskolan i Dalarna.
2009 (engelsk)Inngår i: Invited paper to the International Conference MEFORM 2009, Freiberg, Germany , 2009Konferansepaper, Publicerat paper (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
2009.
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-13989OAI: oai:DiVA.org:kth-13989DiVA, id: diva2:328844
Merknad
QC 20100706Tilgjengelig fra: 2010-07-06 Laget: 2010-07-06 Sist oppdatert: 2010-07-21bibliografisk kontrollert
Inngår i avhandling
1. Modeling the Microstructural Evolution during Hot Deformation of Microalloyed Steels
Åpne denne publikasjonen i ny fane eller vindu >>Modeling the Microstructural Evolution during Hot Deformation of Microalloyed Steels
2009 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

 

This thesis contains the development of a physically-based model describing the microstructural evolution during hot deformation of microalloyed steels. The work is mainly focused on the recrystallization kinetics. During hot rolling, the repeated deformation and recrystallization provides progressively refined recrystallized grains. Also, recrystallization enables the material to be deformed more easily and knowledge of the recrystallization kinetics is important in order to predict the required roll forces. Hot strip rolling is generally conducted in a reversing roughing mill followed by a continuous finishing mill. During rolling in the roughing mill the temperature is high and complete recrystallization should occur between passes. In the finishing mill the temperature is lower which means slower recrystallization kinetics and partial or no recrystallization often occurs. If microalloying elements such as Nb, Ti or V are present, the recrystallization can be further retarded by either solute drag or particle pinning. When recrystallization is completely retarded and strain is accumulated between passes, the austenite grains will be severely deformed, i.e. pancaking occurs. Pancaking of the grains provides larger amount of nucleation sites for ferrite grains upon transformation and hence a finer ferrite grain size is achieved.

In this work a physically-based model has been used to describe the microstructural evolution of austenite. The model is built-up by several sub-models describing dislocation density evolution, recrystallization, grain growth and precipitation. It is based on dislocation density theory where the generated dislocations during deformation provide the driving force for recrystallization. In the model, subgrains act as nuclei for recrystallization and the condition for recrystallization to start is that the subgrains reach a critical size and configuration. The retarding effect due to elements in solution and as precipitated particles is accounted for in the model.

To verify and validate the model axisymmetric compression tests combined with relaxation were modeled and the results were compared with experimental data. The precipitation sub-model was verified by the use of literature data. In addition, rolling in the hot strip mill was modeled using process data from the hot strip mill at SSAB Strip Products Division. The materials investigated were plain C-Mn steels and Nb microalloyed steels. The results from the model show good agreement with measured data.

 

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2009. s. x, 47
Emneord
modeling, austenite, microalloyed steels, hot deformation, microstructure evolution, static recrystallization, dynamic recrystallization, metadynamic recrystallization<
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-10390 (URN)978-91-7415-267-8 (ISBN)
Disputas
2009-04-20, B3, KTH, Brinellvägen 23, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100706Tilgjengelig fra: 2009-05-08 Laget: 2009-05-08 Sist oppdatert: 2010-07-21bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Søk i DiVA

Av forfatter/redaktør
Bäcke, Linda
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric

urn-nbn
Totalt: 121 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf